Nonleptonic two-body weak decays of charmed baryons

We systematically analyze the two-body nonleptonic weak decays of charmed baryons, employing the pole approximation in tandem with the $SU(3)_F$ symmetry. Leveraging the K\"orner-Patti-Woo theorem, we demonstrate a significant reduction in the number of free parameters. Within the general pole scenario, we successfully explain most of the experimental data of ${\bf B}_c^A \to {\bf B}_nP$, though some inconsistencies are detected and recommended for reexamination in future research. Assuming the dominance of low-lying intermediate baryons, we are able to make novel predictions for decay channels such as $\Omega_c^0 \to {\bf B}_n P$ and ${\bf B}_{cc}\to {\bf B}_c^{A,S} P$. Here, ${\bf B}_n$, ${\bf B}_{c}^A$, ${\bf B}_c^S$ and ${\bf B}_{cc}$ are the low-lying octet, antitriplet charmed, sextet charmed and doubly charmed baryons, respectively, and $P$ is the pseudoscalar meson. Our findings also reveal that the fitted effective Wilson coefficient ${\cal C}_+=0.469$ is notably smaller than the na\"ive expectation, and the low-lying pole scenario fails to account for ${\cal B}(\Lambda_c^+ \to n \pi^+ , \Xi^0 K^+)$ , despite consistencies with the soft meson limit. We further recommend the decay channel $\Xi_{cc}^+ \to \Xi_c^0 \pi^+ \to \Xi^- \pi^+\pi^+\pi^+\pi^-$ for exploring evidence of $\Xi_{cc}^+$, estimating the branching fraction at $(1.1\pm 0.6)\times 10^{-3}$. The predictions for nonleptonic weak decay channels are compiled in the appendices, providing valuable references for future experimental validation.Comment: 37 pages, 3 figure

Singly Cabibbo suppressed decays of Λc+\Lambda_{c}^+ with SU(3) flavor symmetry

We analyze the weak processes of anti-triplet charmed baryons decaying to octet baryons and mesons with the SU(3) flavor symmetry and topological quark diagram scheme. We study the decay branching ratios without neglecting the contributions from ${\cal O}(\overline{15})$ for the first time in the SU(3) flavor symmetry approach. The fitting results for the Cabibbo allowed and suppressed decays of $\Lambda_{c}^+$ are all consistent with the experimental data. We predict all singly Cabibbo suppressed decays. In particular, we find that ${\cal B}(\Lambda_c^+\to p \pi^0)=(1.3\pm0.7)\times 10^{-4}$, which is slightly below the current experimental upper limit of $2.7\times 10^{-4}$ and can be tested by the ongoing experiment at BESIII as well as the future one at Belle-II.Comment: 11 pages, 2 figure, revised version accepted by PL

Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

We study the semileptonic and non-leptonic charmed baryon decays with $SU(3)$ flavor symmetry, where the charmed baryons can be ${\bf B}_{c}=(\Xi_c^0,\Xi_c^+,\Lambda_c^+)$, ${\bf B}'_{c}=(\Sigma_c^{(++,+,0)},\Xi_{c}^{\prime(+,0)},\Omega_c^0)$, ${\bf B}_{cc}=(\Xi_{cc}^{++},\Xi_{cc}^+,\Omega_{cc}^+)$, or ${\bf B}_{ccc}=\Omega^{++}_{ccc}$. With ${\bf B}_n^{(\prime)}$ denoted as the baryon octet (decuplet), we find that the ${\bf B}_{c}\to {\bf B}'_n\ell^+\nu_\ell$ decays are forbidden, while the $\Omega_c^0\to \Omega^-\ell^+\nu_\ell$, $\Omega_{cc}^+\to\Omega_c^0\ell^+\nu_\ell$, and $\Omega_{ccc}^{++}\to \Omega_{cc}^+\ell^+\nu_\ell$ decays are the only existing Cabibbo-allowed modes for ${\bf B}'_{c}\to {\bf B}'_n\ell^+\nu_\ell$, ${\bf B}_{cc}\to {\bf B}'_c\ell^+\nu_\ell$, and ${\bf B}_{ccc}\to {\bf B}_{cc}^{(\prime)}\ell^+\nu_\ell$, respectively. We predict the rarely studied ${\bf B}_{c}\to {\bf B}_n^{(\prime)}M$ decays, such as ${\cal B}(\Xi_c^0\to\Lambda^0\bar K^0,\,\Xi_c^+\to\Xi^0\pi^+)=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3}$ and ${\cal B}(\Lambda_c^+\to \Delta^{++}\pi^-,\,\Xi_c^0\to\Omega^- K^+)=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}$. For the observation, the doubly and triply charmed baryon decays of $\Omega_{cc}^{+}\to \Xi_c^+\bar K^0$, $\Xi_{cc}^{++}\to (\Xi_c^+\pi^+$, $\Sigma_c^{++}\bar K^0)$, and $\Omega_{ccc}^{++}\to (\Xi_{cc}^{++}\bar K^0,\Omega_{cc}^+\pi^+,\Xi_c^+ D^+)$ are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.Comment: 29 pages, no figure, a typo in the table correcte

Hidden Trends in 90 Years of Harvard Business Review

In this paper, we demonstrate and discuss results of our mining the abstracts of the publications in Harvard Business Review between 1922 and 2012. Techniques for computing n-grams, collocations, basic sentiment analysis, and named-entity recognition were employed to uncover trends hidden in the abstracts. We present findings about international relationships, sentiment in HBR's abstracts, important international companies, influential technological inventions, renown researchers in management theories, US presidents via chronological analyses.Comment: 6 pages, 14 figures, Proceedings of 2012 International Conference on Technologies and Applications of Artificial Intelligenc

Center of mass motion in bag model

Despite the great success on the mass spectra, the reputation of the bag model has been closely followed by the embarrassment from the center of mass motion. It leads to severe theoretical inconsistencies. For instance, the masses and the decay constants would no longer be independent of the momentum. In this work, we provide a systematical approach to resolve this problem. The meson decay constants as well as the baryon transition form factors can be computed consistently in our framework. Notably, the form factors in the neutron $\beta$ decays do not depend on any free parameters, and are determined to be $F^V_1 =1$ and $F^A_1 = 1.31$ or $F_1^A/F_1^V= 1.31$, which is close the experimental value of $F^A_1/F^V_1 = 1.27$. In addition, we find that ${\cal B} (\Lambda_b \to \Lambda \gamma) = (6.8 \pm 3.3 ) \times 10^{-6}$, which agrees to the experimental value of $(7.1\pm 1.7)\times 10^{-6}$.Comment: 21 pages, 2 figure

Nonleptonic decays of Ξcc→Ξcπ\Xi_{cc}\to \Xi_c \pi with Ξc−Ξc′\Xi_c-\Xi_c' mixing

Aiming on testing the $\Xi_c-\Xi_c'$ mixing, we study the decays of $\Xi_{cc}\to \Xi_c \pi$ with $\Xi_{cc} = (\Xi_{cc}^{++} , \Xi_{cc} ^+ )$, $\Xi_c = (\Xi_c^{(\prime)+},\Xi_c^{(\prime)0})$ and $\pi = (\pi^+ , \pi^0)$. The soft-meson limit is considered along with the pole model, and the baryon matrix elements are evaluated by the bag model with and without removing the center-of-mass motion (CMM). We find that the four-quark operator matrix elements are about twice larger once the unwanted CMM is removed. We obtain that ${\cal R} = {\cal B}(\Xi_{cc}^+ \to \Xi_c^{\prime +} \pi^+ )/ {\cal B}(\Xi_{cc}^+ \to \Xi_c^{ +} \pi^+ ) = 0.87^{+0.17}_{-0.11}$ and $1.45$ with and without removing the CMM, where the former is close to the lower bound and the later is well consistent with ${\cal R} = 1.41 \pm 0.17 \pm 0.10$ measured at LHCb. In addition, we show that after including the mixing, the up-down asymmetry of $\alpha( \Xi_{cc}^+ \to \Xi_c^{(\prime)0 } \pi^+)$ flips sign. Explicitly, we obtain that $\alpha(\Xi_{cc}^{+} \to \Xi_c^{\prime +} \pi^0) = 0.52$ and $\alpha(\Xi_{cc}^{+} \to \Xi_c^{ 0 } \pi^+) = 0.31$ with and without the CMM corrections, respectively, which are all negative if the mixing is absence. As a bonus, a positive value of $\alpha(\Xi_{cc}^{+} \to \Xi_c^{\prime 0} \pi^+)$ in experiments can also serve as the evidence of the $W$-exchange contributions.Comment: 17 pages, 1 figure, accepted by Physical Review